Clogged arteries are often treated in a minimally invasive manner by the use of a balloon which is inflated at a clogged location and/or using a stent which maintains the patentcy of a clogged location. As a catheter carrying a balloon and/or a stent are often difficult to navigate through the vascular system, and are also difficult to insert into a clogged location, common practice is to first guide a thin guidewire in conjunction with a guide-tube to the clogged location. Often, several guidewires need to be tried until a suitable one is found. The guidewire maybe replaced by a thinner guidewire after the guide-tube reaches the clogged location. A catheter (e.g. a balloon catheter) is then provided over the guidewire and through the tube. As the guidewire is in place, the catheter can be removed and a different catheter, with a different tool provided over the guidewire and optionally through the guide-tube (also known as a guiding catheter). If the guidewire needs to be replaced, it can be exchanged in some systems, for example, using the guide-tube, so that the replacement guidewire can follow the same exact path, being guided by the tube. Nevertheless, since guidewires are long (˜2 meters) such exchange is a time consuming process.
Various guidewire-catheter systems have been devised, included, for example systems in which the guidewire is contained in a passage along the catheter (e.g., U.S. Pat. No. 5,324,269), systems in which the passage is partial (e.g., U.S. Pat. Nos. 5,468,225 and 5,554,118) and a system in which the passage is defined as part of a balloon (e.g., U.S. Pat. No. 6,007,517). The disclosure of all of these patents is incorporated herein by reference.
US patent publication 2002/0032457A1, the disclosure of which is incorporated herein by reference, describes a catheter in which a balloon portion can be exchanged without replacing the catheter.
U.S. Pat. No. 5,195,978, the disclosure of which is incorporated herein by reference, describes a catheter in which a guidewire can be rapidly removed from the catheter by tearing a portion of a catheter guidewire channel off, outside of the body. In U.S. Pat. No. 5,472,425, the disclosure of which is incorporated herein by reference, the guidewire itself tears the channel open, again, apparently outside the body and the guidewire may also be used to create an exit port from the catheter at a chosen location. However, there is no suggestion or reason for creating an exit at the balloon.
One complicated situation is that of a bifurcation stent implantation. Here, two guidewires are generally provided, one for each side of the bifurcation. U.S. Pat. No. 6,325,826 and US patent application publication 2001/0049548 A1, U.S. Pat. No. 6,210,429, WO 00/74595 and WO 99/36002, the disclosures of which are incorporated herein by reference, describe various two guidewire systems. All of these systems, however, seem to require a guidewire sheath for each guidewire, as a separate catheter, as a separate sheath inside a stent to be deployed or as a previously extended sheath. This may add undesirable complexity or thickness to the delivery system. Balloons for the two branches are inflated sequentially, one after the other is retracted.